Object expected error in doReq

[HenryV]

I display an image on the screen and when clicked, it is to display an FAQ page

Here is the html code, which when clicked gives an error "object expected". I use the exact code in a diffrent program without any problems

<td ><img id='obj' src='images/Help2Big.gif'            style='cursor:hand;' alt='Frequently Asked Questions'  onclick="doReq('faq',this.pg);" ></td>               
 
 

Here is the javacript

<script>
function doReq(obj, loc)
{
    Switch (obj)
    {
        Case "faq":
           window.showModalDialog("Faq.asp","Dialog Arguments Value","dialogHeight:800px; dialogWidth: 500px; edge: Raised; center: Yes; help: No; resizable: NO; status: No;");
                break;    
    }
}
</script>
 

Help appreciated